Establishment and characterization of a cell line from tilapia brain for detection of tilapia lake virus

Tilapia lake virus (TiLV) is an emerging disease threatening tilapia culture in many parts of the world. A cell line from the brain of tilapia, which was named TiB, was established, characterized and subcultured with more than 100 passages. The TiB cell line was optimally maintained at 27 degrees C using medium 199 (M199) supplemented with 10% foetal bovine serum (FBS). Chromosome analysis revealed that 60% of TiB cells at passage 5 maintained the modal chromosome number 2n = 44, while at passage 60, there were 43% of TiB cells with the diploid chromosome number 2n = 50. A significant cytopathic effect was observed in TiB cells after infection with tilapia lake virus (TiLV-2017A), and the viral replication in the cells was confirmed by transmission electron microscopy, immunofluorescence assays and viral titres, indicating the susceptibility of TiB cells to TiLV-2017A. The viral titres of TiLV-2017A in TiB cells reached 10(7.43) TCID50/ml within 10 days. The stable growth and susceptibility to fish viruses make TiB cells a useful tool for fish virus-host cell interaction and for immune response of fish.